Had an interesting conversation tonight about 5.56 with a buddy of mine. Guy is super smart and has every firearm under the sun. He said: “5.56 is dead. If inside of 200 yards, use 300BLK. Over 200 yards, go with .260, 6.5 or .308.”

Obviously, 5.56 isn’t going anywhere anytime soon, but I did find it an interesting point. You guys agree or disagree?

I dont think it’s dead, it’s just so common that it’s not in the spotlight anymore. I personally love everything about the caliber but I do understand his point of view. It does what it’s designed to do and it’s so abundant and cheap that it’s hard to break away from. The combination of being lightweight, accurate, relatively cheap, and having manageable recoil is hard to beat.

Ammo cost, availability and the millions of civilian ARs will keep it around for a while. Military is developing that new 6.8 round but if not done right it could be another expensive DOA project. Design by committee is a recipe for disaster.

In my opinion and it might not be a popular one, 6.8 SPC II is the round that NATO should have adopted for their infantry issue carbines. Better performance and knock-down power out of shorter barrels at longer ranges compared to 5.56. It is better in every way. Plus, I’d take a 6.8 SPC over 308 all day long. Extra weight of 308 plus the extra weight of the ammo is a killer whether you’re hunting game or enemy combatants. Not to mention the case design of the 6.8 is so good that Federal chose it for the .224 Valkyrie which I love to shoot. The casing is also the advantage over a round like the 6.5 Grendel. The case also allows for thicker webbing between the lugs of the bolt which is huge when it comes to durability. Take a look at the extra brass in the base of the casing of the 6.8:

I’m not an expert on 300BLK but from all that I’ve read and been told by people who know more than I do, it is now simply the best cartridge for SMG style weapons. Pistol caliber rounds just can’t keep up. They’re quiet, made for short barrels and can reach out a bit when needed. I am really curious about penetration though. Is that a limitation of 300 blackout? From what I understand, it is velocity that you’re looking for when trying to penetrate barriers. And if that is the case then 300 BLK actually might not be the best “do everything within 200 yards” round. 95gr 6.8 SPC factory loads are leaving the muzzle at up to 2900 fps. Maybe someone can chime in here to educate me on this issue of penetration.

The 6.5 Creedmoor is definitely the way to go for large platform and it’s performance can justify the extra weight of the rifle and ammo. I think this is pretty well established.

So the question here seems to be, do we need something between the 300 BLK and 6.5 Creedmoor. If the 300 BLK lacks lethality through barriers then it could be that to cover all scenarios, we still need: SMGs in 300BLK, M4 style carbines in (maybe in 6.8) and a long range semi-auto solution in 6.5 Creedmoor.

Good topic and I’m very much looking forward to being educated on any false assumptions I’m making here.

I’ve never been fond of the round but it’s near universal availability and price will keep it alive for the foreseeable future. Other calibers based on the 5.56 case that share BCG’s and mags are a good thing for me. I shoot an AR chambered in Wilson Combat’s 300HAM’R. Converting 5.56 range brass is easy and cheap. It’s sub moa and exceeds 30-30 ballistics. Since I figure most of the shots I take will be under 300 yards my need for 7.62 has diminished. All I have in that caliber anymore is an M1A SOCOM. I load Speer 125 gr TNT and Speer 150gr SPBT interchangeably between my 300HAM’R and M1A. Prior to getting my HAM’R 5.56 was in fact dead (to me) and I didn’t have enough interest 300BLK to bother with building either. Now I can justify building a couple of uppers to keep around just in case. Ironically this may help keep 5.56 alive.

Just getting into the build aspect of the ar. Bought a 300blk upper from a bud of mine just to have a bit more umph than a .556 and a semi automatic for hog hunting. Question being which upper would be the logical progression?

My recommendation would be take a look at a quality 6.5 Creedmoor upper eventually. My last build was an 8” 300blk…my next long term purchase is an eventual KAC SR-25 in 6.5 Creedmoor, whenever that gets released

6.5 Grendel is a more mature long range small platform cartridge compared to the .224. More reloading data available, more factory ammo, more bullets, more barrels. In theory the .224 has the potential to surpass the Grendel for long range small platform shooting but it isn’t there yet.